The company’s U.S.-listed shares slumped as much as 30 percent to a five-year low of $7.40, making them the biggest percentage loser on the Nasdaq.

At least six brokerages cut their price targets on the stock, ranging between $5 and $20.

Adoption of Westport’s technology has been frustratingly slow in the United States and Canada, where natural-gas fueling stations remain scarce and cheaper diesel engines have become more efficient.

“Shares are now in a ‘show-me’ situation and it could be several months before improvement is clear,” Lake Street Capital Markets analyst Robert Brown said in a note. The brokerage downgraded the stock to “hold” from “buy”.

The company lowered its 2014 revenue forecast to $130 million-$140 million from $175-$185 million on Tuesday.

Analysts on average were expecting revenue of $178.7 million, according to Thomson Reuters I/B/E/S.

Apart from supplying its patented technology, Westport makes components such as pressure regulators and injectors used by car makers including Volkswagen AG, General Motors Co and Fiat SpA.

Revenue from the components business, which accounts for more than half of the total revenue, fell in the second quarter primarily due to weakness in the European market.

Westport sales have been below analysts’ expectations in five of the last eight quarters.

The company said it still expects to turn profitable on a consolidated adjusted core earnings basis by the end of 2015. It is yet to turn a profit since listing in Toronto 15 years ago.

“We are skeptical this target will remain intact,” JPMorgan analyst Ann Duignan said in a note.

Westport’s Toronto-listed shares, headed for their biggest single-day fall, were down 23 percent at C$9.04 on Wednesday. (Reporting By Darshana Sankararaman)